
whose chemical name is [(−)-(6R,7R)]-7-{[(Z)-2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamido}-8-oxo-3-vinyl-5-thia-1-azabicyclo [4.2.0] oct-2-en-2-carboxylic acid, is a third generation semisynthetic cephalosporin for the oral use, characterized by a broad antibacterial activity spectrum and by antibiotic activity against gram-positive and gram-negative bacteria higher than that of other antibiotics for the oral administration. In particular, cefdinir shows an excellent antibacterial activity against staphylococci and streptococci.
Cefdinir is usually prepared through processes which envisage the protection of one or more of the primary amino, hydroxyimino or carboxy functions. The protective groups are removed at the end of the synthesis by means of acid hydrolysis.
U.S. Pat. No. 4,559,334 discloses a method for the preparation of cefdinir benzhydryl ester, which is hydrolysed with TFA in anisole or with BF3.Et2O.
WO 01/79211 teaches to prepare cefdinir via protection of the hydroxyimino and carboxy functions with a benzhydryl and a p-methoxybenzyl group respectively, which are subsequently removed with perchloric acid in an aprotic solvent and in the presence of an organic acid.
WO 97/24358 dicloses the preparation of a cefdinir salt with p-toluenesulfonic acid wherein the hydroxyimino function is protected with a trityl group.
Since cefdinir is poorly stable to acids, the aforementioned methods give sometimes unsatisfactory yields and the purity does not comply with the pharmacopoeia standards. The resulting product must therefore be subjected to further purification, for example to recrystallization (according to U.S. Pat. No. 4,935,507) or to formation of salts (according to U.S. Pat. No. 6,350,869).